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Seed

According to pumpkin grower extraordinaire, Clive Bevan, the key to growing a mammoth pumpkin is getting the right seed. Clive has selected every year from the biggest and best in his and others' gardens. He doesn't grow one named variety (such as 'Atlantic Giant'), but has crossed three or four different cultivars over many years.

Fertiliser

Once you've sourced your seed, you need to get the ground right, digging over the area you're going to plant now, in the autumn, and adding plenty of manure - pumpkins are greedy. Then you need to fine-tune the site for the root. Dig a big hole and fill it with a couple of barrows full of farmyard manure, then return some of the soil. Finally, cover the area with a plastic sheet to warm it through winter.

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When and where to sow

Pumpkins grow at enormous speed, so there's no point sowing until the last week of April. With a sharp knife, cut down each side of the pumpkin seed so it looks like an arrowhead. This takes the strength out of the sides of the seed hull and allows the first root to emerge more quickly. Then place the seed somewhere warm and cosy, on its side on a damp cloth. Clive advises putting it into an airing cupboard and keeping it at 24C (75F). Meanwhile, warm the compost in a 9cm (3½in) pot.

Transferring plants

Within three or four days, the first "radical" root appears. When this is about 5cm (2in) long, transfer the seed to the pre-warmed compost. Don't bury it, but put it on the surface, standing upright, with its roots going straight down. Put it in bright light in a protected place indoors.

The seedling will start to grow quickly, with the seed leaves emerging as well as the root. Now you need to squeeze the seed hull gently to remove it from the nascent seedling. It will open like a purse, leaving two mature seed leaves. The seed hull often sticks and damages one or both of a pumpkin's seed leaves, but you need both intact to produce a good plant.

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Potting up

After this, keep moving your plants on, potting them up into successively larger pots. Once they reach a 1 litre size, the plant should be big enough to put out into its permanent position.

Tips and tricks

There are many other tips, but only two vital bits of advice. Once the main stem is about 90cm (3ft) long, dig a trench one spit deep and one spit wide. In the bottom, put a thin layer of compost or manure, then a thin layer of soil, and place the growing stem on that. It will continue growing down the trench and every leaf joint will develop roots. Cover these with soil in a mound, and you'll have the makings of prize-winning pumpkins.

You'll need to feed it a high-nitrogen fertiliser - such as soaked chicken pellets - watered in with warm water. Feed almost every day until the pumpkin is mature, then change to a potash feed to bulk up the flesh and the seed inside. This maximises the pumpkin's weight.

So don't wait until spring. Start now, and let's see who can grow the biggest.